Counterbalance for crankshafts



Dec. 5, 1939. J wRlGLEY I 2,182,740

COUNTERBALANCE FOR CRANKSHAFTS Filed Dec. 18, 1937 2 Sheets-Sheet 1 Ira--1 Dec. 5, 1939.

' COUNTERBALANCE FOR CRANKSHAFTS Filed Dec. 18, 1937 2 Sheets-Sheet 2 J. B. WRIGLEY 2,182,740

Patented Dec. 5, 1939 UNITED STATES 2,182,7 0 COUNTERBALANCE FOR CRANKSHAFTS James B. Wrigley, Tulsa, Okla., assignor to International Supply Company, Tulsa, Okla., a corporation of Delaware Application December 18, 1937, Serial No. 180,652

3 Claims.

This invention relates to improvements in counterbalances for crankshafts, and more particularly to counterbalancing means for crankshafts employed in well pumping and drilling equipment. I

Heretofore, in devices of this character, counterbalances or counterweightshave been provided on the crank disc or crank arm, and in such instances, the weights usually projected outwardly beyond the periphery of the disc. This, of course, creates a hazard for the employees working in the vicinity of such equipment. Furthermore, due to the fact that the counterweights in these prior devices extend beyond. the periphery of the disc, the latter is usually made relatively small, or in the event the pumping requirements necessitate the use of a large crank disc, the latter must be raised a considerable distance from the ground in order to provide sufficient clearance for the projecting counterweights.

It is therefore the primary object of my invention to provide counterweight means for the crank discs which will lie entirely within the periphery of the disc.

A further object is to supply a crank disc of special construction which will facilitate the handling of said disc and the assembly thereof on the pumping or drilling unit.

Another object resides in the particular structure and arrangement of parts whereby the adjustment of the positions of the weights on the crank disc within the periphery of the latter, and the position of the disc on the crankshaft may be easily performed.

With the above and other objects in view, the invention will now be described in conjunction with the accompanying drawings, in which,

Fig. 1 is a side elevation of one embodiment of my invention, showing the crank arm, the crank disc and the counterweights secured to the latter.

Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is a side elevation showing another embodiment of the principles of my invention.

Fig. 4 is a vertical sectional view of the same,

taken on the line 4-4 of Fig. 3.

Referring to the drawings in detail, and particularly to Figs. 1 and 2, the numeral 5 designates a cast metal circular crank disc having cut-out portions forming substantially semicircular apertures B and l. A pair of longitudinally extending substantially diametrically disposed ribs 8, 9, preferably formed integral with the web portion 5a. of the disc, separate the holes 6 and 1 from one another. These ribs are spaced apart to form a substantially rectangular diametrical recess 10 which is adapted to receive a portion of the crank arm II, as will be hereinafter described. Each ribis provided with a longitudinal row of spaced apertures l2.

The crank arm is provided at one end with a bearing member l3 which is keyed or otherwise fixed to the crankshaft (not shown) of a. conventional well pumping and drilling unit. As shown in the drawings, the crank arm is adapted to extend mainly within the recess i ii of the disc, and is provided with oppositely disposed pairs of ears I4 having apertures which may be brought. into alignment with the apertures I2 on the ribs 8, 9, for diametrically adjusting the disc relatively to the crank arm; Bolts l6 extend through the apertures for securing the disc to the crank arm at the desired'position.

In practice, the crank disc may be readil adjusted diametrically relatively to the crank arm by simply removing the bolts l6 and moving the disc diametrically until the apertures in the oppositely disposed pairs of ears come into align- I ment with certain of the apertures on the ribs 8, 9. In thismanner, the bearing member of the crank arm may be disposed approximately centrally of the disc, so that the peripheral edge of said disc extends equally from the crankshaft, or, if desired, the disc may be moved diametrically along the crank arm to a position whereby the crank bearing member will be ofiset relatively to the center of the crank disc, so that the weight of the disc will be eccentric relative to the crankshaft upon which the disc is supported.

The crank arm also has a longitudinally arranged row of apertures or holes ll adapted to receive awrist pin (not shown) for connecting the pitman of a conventional pumping or drilling unit with the crank arm. Due to the arrange- 40 ment of these last mentioned apertures on the crank arm, the pitman may be connected to the crank arm at various positions toward or away from the bearing I3, to take care of variations in the length of stroke required of the pitman in pumping or drilling operations.

\ As will be noted from Fig. 2, the web portion 5a. of the crank disc is substantially T-shaped in radial section, with the head I8 of the T forming a peripheral flange on each side of the web. One or more counterweights l9, preferably of arcuate shape, may be detachably connected to the crank disc by means of bolts 20 which extend through apertures in the weights and openings 2| in the disc. As will be noted, the disc is provided with a 55 plurality of such openings 2! about its circumference so that the weights may be circumferentially adjusted to various positions.

The counterweights (Fig. 2), are formed of two duplicate parts or sections 23, 24, of arouate shape, which are clamped by the bolts 20 at each side of the web portion of the crank disc. As noted in Fig. 2, each section has a countersunk bore 25 to receive the head or nut of the bolt. Furthermore, it will be observed that the sect'ons 23, 24, of the counterweights contact the flanges l8, and each of said sections is preferably of a thickness approximately equal to the width of each flange, so as to present a substantially plane ouler surface on the crank disc when the weights are secured in place thereon.

Owing to the diametrical adjustment of the crank disc relatively to the crank arm and its bearing member, the duplicate sections or parts of the counterweights may all be made of the same size and weight, and any requirement for additional counterbalancing effect not capable of fulfillment by these weights may be compensated ior by this adjustment.

Furthermore, due to the fact that the counterweights are arranged within the periphery of the disc, the possibility of the operator being caught or hit by the counterweights will be eliminated. Also, with a structure of this character, a larger type fly wheel or crank disc can be employed which will increase the disc inertia, thus smoothing out the action of the working parts of the pump and functioning in a manner similar to a large fly wheel on an automobile.

In addition, it will be noted that owing to the arrangement of the counterweights within the periphery of the crank disc, the work of changing the weights or adjusting them to other positions about the circumference of the disc is greatly facilitated.

Referring now to the embodiment of the invention shown in Figs. 3 and 4, I have shown a counterbalancing means for crankshafts of pumping and drilling apparatus which is quite similar to that described in connection with Figs. 1 and 2. The crank disc 5b in this modification, however, is made up of two parts or sections 50, 5d. Each section includes a semicircular web portion 5e and a diametrically disposed rib 8a. Each rib includes a portion of the crank arm Ila, and a flange 30 arranged at right angles to the plane of the web portion and provided with apertures adapted to receive bolts 32 for use in clamping the two semi-circular portions of the disc together. The counterweights in this embodiment of the invention are adjustably secured to the web portion of the crank disc in a manner similar to that described in connection with Figs. 1 and 2.

Making the crank disc of two sections facilitates the assembly or disassembly of the counterbalancing unit on the crankshaft, and of course, when the sections are assembled in the manner illustrated in Fig. 3, the disc will function with the efficiency of a disc made of a single casting.

While I have shown the crank disc in Fig. 3 made up of two sections, it will be understood that the disc in this embodiment of the invention may be made of a single casting, with the two ribs Ba forming a single diametrically disposed rib. Of course, with this embodiment of the invention, the disc cannot be adjusted relatively to the crank arm.

While I have described particular embodiments of my invention, it has merely been for the sake of illustration and I do not wish to be limited to those particular embodiments, as it is obvious that many changes in details of construction may be made within the scope of the claims.

What I claim and desire to secure by Letters Patent is:

1. In a device of the character described, a crank disc comprising a substantially flat circular web bound by a circular flange which extends outwardly beyond opposite sides of the web, substantially arc-shaped weights adjustable approximately 360 degrees about the peripheral portion of the disc, said weights being arranged at opposite sides of the web and having their outer ends contacting the inner surface of the flange, each weight having its inner edge spaced a material distance from the axis of the disc, means adjustably securing the weights to the web, and a crank arm extending diametrically of the disc and having a series of apertures positioned radially of the disc between the center of the latter and an annular line concentric with said center and defining the inner edges of said weights.

2. In a device of the character described, a crank disc comprising a substantially fiat annular web bound by a circular flange extending outwardly beyond opposite sides of the web, rib means extending diametrically across the disc and connecting diametrically opposite portions of the inner edge of the web, substantially arcshaped weights adjustable for substantially 360 degrees about the peripheral portion of the disc, said weights being arranged at opposite sides of the web and having their outer ends contacting the inner surface of the flange and their inner ends spaced a material distance from the axis of the disc, means adjustably securing the weights to the web, and a crank arm forming part of said rib means and having a series of apertures positioned radially of the disc between the center of the latter and an imaginary line concentric with said center and defining the inner ends of said weights.

3. In a device of the character described, a crank disc comprising a substantially fiat circular web bound by a circular flange which extends outwardly beyond opposite sides of the web, said web having a circular series of apertures extending for substantially 360 degrees about the peripheral portion of the disc, weights arranged at opposite sides of the web and having outer edges contacting the inner surface of the flange, bolts passing through the weights and through apertures of the web for securing the weights at different angular adjustments about the axial center of the disc, the thickness of each weight being not more than the distance between either side surface of the web and the adjacent edge of the flange, each weight having its inner edge spaced a material distance from the axis of the disc, and a crank arm extending diametrically of the disc and having a series of apertures positioned radially of the disc between the center of the latter and a circular line concentric with said center and coinciding with the inner edges of said weights,

JAMES B. WRIGLEY.

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